Microbial decolorization of molasses waste water by Mycelia Sterilia D90.

Abstract

Three kinds of molasses waste water were collected from the stillage of an alcohol factory, and an anaerobic and an aerobic pond of its waste water treatment plant, respectively, and their chemical properties, such as chemical oxygen demand value, biological oxygen demand value and so on, were examined in this study. Mycelia Sterilia D90 decolorized about 90% of the molasses pigment in 10 days and at the same time caused an about 80% decrease in the biological oxygen demand value when glucose 2.5%, NaNO3 0.2%, KH2PO4 0.1% and MgSO4•7H2O 0.05% were added to the molasses waste water from the stillage as nutrients. But without supplementation of the nutrients, the decolorization yield was only 17.5%. Furthermore, this strain showed a decolorization yield of about 70% in 11 days and caused a decrease in the biological oxygen demand value of about 90% in 15 days under non-sterile conditions. In the fed-batch system, this strain showed a constant decolorization yield of about 80% and caused a decrease in the biological oxygen demand value of about 70% during three times replacement (24 days).